The present invention relates to fluidized patient support surfaces and more particularly to fluidized patient support surfaces with the capability of changing the fluidization characteristics of the patient support surface.
Fluidized patient support surfaces have been used for treating patients confined to beds for long periods of time. Many examples are found in the patent literature, including Hargest et al U.S. Pat. Nos. 3,428,973; Hargest U.S. Pat. No. 3,866,606; Lacoste U.S. Pat. No. 4,481,686; Paul U.S. Pat. No. 4,483,029; Goodwin U.S. Pat. No. 4,564,965; Goodwin U.S. Pat. No. 4,637,083; Hargest et al U.S. Pat. No. 4,914,760; Hargest et al U.S. Pat. No. 4,942,635; Hargest et al U.S. Pat. No. 4,967,431; Vrzalik U.S. Pat. No. 5,008,965; Hargest et al U.S. Pat. No. 5,029,352; and Hargest U.S. Pat. No. 5,036,559; all of which except the patent to Vrzalik being hereby incorporated herein by this reference. Intermittently turning the fluidization of the entire support surface on and off is disclosed in Hargest U.S. Pat. No. 3,866,606. Sequentially turning the fluidization on and off under successive discrete portions of the fluidized patient support system is disclosed in Goodwin U.S. Pat. No. 4,637,083, which subjects the patient to fluidization beneath different portions of the patient's body at any given moment in time.
It is known that the application of undulating or vibratory action to the area of the body adjacent to the thoracic cavity, can induce postural draining or coughing up of sputum, thereby reducing the amount of mucous that lines the inner walls of the alveoli. Therapeutic percussors and vibrators have been used to stimulate expectoration of mucous from the lungs. Examples of various pneumatic and mechanical types of percussors would include those disclosed in Strom et al U.S. Pat. No. 4,508,107 and Maione U.S. Pat. No. 3,955,563. Heretofore, such external mechanical or pneumatic types of percussors would be needed to provide percussive chest therapy to induce mucociliary clearance for a patient resting in an air fluidized bed. The external percussor would be applied directly to the patient's upper torso to loosen the mucous.